The TypeScript team has reworked the compiler core of TypeScript to be lighter and faster and has moved the project to GitHub.
After experimenting with a new, lighter-weight compiler core, and having seen very positive early results, the TypeScript team plans on using the core in the new TypeScript compiler and language service.
This will happen in stages, starting with the creation of a complete standalone compiler based on this new core architecture. The new compiler follows the same TypeScript 1.0 language spec, has the same compiler flags and compiler functionality, and outputs nearly identical code to the currently shipping TypeScript compiler. When the team is happy the compiler is complete, it should be drop-in compatible with the existing one.
“the goal here isn't new compiler features, but rather a cleaner compiler architecture that has better performance and allows us to add new features with greater ease in releases to come.”
The performance improvements in the new compiler are impressive; at its current level of completeness, the new compiler is able to compile existing real-world TypeScript code five times faster than the currently shipping compiler.
As yet the compiler is incomplete in feature terms; the parser needs to have Strict mode added, along with incremental parsing for the language service. Type checking is nearing completion, but still needs work on its error coverage, while the compiler options are missing support for --propagateEnumConstants, --watch, --locale, --logFile and --version.
The developers also need to adapt the language service to work with new compiler, and to add comment preservation to the emitter.
Turner says “As we reach parity with our existing compiler, we’re looking forward to moving on to ECMAScript 6 features and exploring the top user requests.”
Alongside the new compiler, and in response to feedback from its community, the team is moving to entire TypeScript project to Github.